This application relates to a gas turbine engine wherein the spinner, located forwardly of the fan rotor, has an improved shape.
Gas turbine engines are known and, typically include a fan delivering air into a bypass duct as propulsion air. Air is also delivered into a compressor where it is compressed and delivered into a combustion section. The air is mixed with fuel and ignited in the combustion section, and products of this combustion pass downstream over turbine rotors driving them to rotate.
A spinner has typically been placed forwardly of the fan rotor and is a generally solid part, which may also be known as a nosecone. The spinner presents a forward most portion of the gas turbine engine and directs air toward the fan rotor.
However, the spinner may also deflect debris. It has been known to utilize conical shaped spinners, however, these channel debris, such as stones, directly into the fan rotor and, thus, into the compressor. This is, of course, undesirable.
It has also been known to utilize a spinner which has an effective elliptical or parabolic shape in cross-section. This does a better job of “bouncing” foreign objects away from the fan rotor and the core of the engine. However, this comes at the expense of higher drag and resulting lower total pressure recovery going into the fan root.
Historically, the fan rotor has been driven at the same speed as a fan drive turbine rotor. This has limited the speed of the fan drive turbine rotor due to limitations on the speed of the fan rotor.
However, recently it has been proposed to employ a gear reduction between the fan rotor and the fan drive turbine. This has allowed the fan drive turbine to rotate at higher speeds, and has also allowed the fan rotor to increase in diameter. With this increase in diameter, there has also been an increase in bypass ratio. The bypass ratio is a ratio of the volume of air delivered into the bypass duct compared to the volume of air delivered into the compressor.
As the bypass ratio becomes higher, it becomes more important to efficiently utilize the air delivered into the compressor.